after you get some cases thru your 3.5, you can drop your dwell and few ms.
im at 24.2 with the sfr at the 3oclock position (all the way down). that helps. not much else you can do.
you might be able to go a little lower on the dwell.. i didnt mess too much with mine. shoots fine right there.
edit: i have a gsl. so its almost the same as the 3.5